This contains the Explication of the Catapulta, which was a Machine of War used by the Ancients to dart Javelins of an extraordinary bigness. A are the two Beams one against the other, and joyn'd, which after having been drawn, pushed the Javelin with great force when they were unbent. There is one of these Beams, which is represented as being joyned to the Capital of the Machine by an Iron Pin, the other ready to be joyned when the Master of the Machine sounds the Cord with his right Hand, shall have it heightned or let down, the end marked C, as much as is necessary, to give it an equal Bent to the other. This is done by the help of an excentrical piece, which is traversed by a Cylinder, which the Master turns with a Laver, which he holds in his left Hand. D, E E is the Capital of the Catapulta. EE are the holes through which the Rope passeth to draw the Beams. F is the end of one of the Beams represented in great. G is one of the Pins which travers'd a round Eye, by the help of which the Beam is joyned to the Capital. H is the Cylinder which traverses the excentrical piece I. This Plate relates to _pag._ 155. [Illustration: Plate XI.] _Explication of the Hardest Terms in_ Architecture. A _Abacus_, from [Greek: abax]; which signifies a square Trencher: In French it's called _Talloir_; it's that quadrangular Piece commonly accompanied with a _Cymatium_, and serves instead of a _Drip_ or _Corona_ to the Capital. It supports the nether _Face_ of the _Architrave_ and whole _Trabeation_. In the _Corinthian_ and the _Compound_ Orders, its Corners are called the _Horns_, the intermediate _Sweep_ and _Curvature_; the Arch, which has commonly a _Rose_ carved in the middle. _Acroteria_ or _Acroter's_ from [Greek: akron], _Summa pars_; they may be properly called _Pinnacles_, for _Pins_ and _Battlements_ were made sometimes more towring; but when they stood in _Ranges_ with _Rails_ and _Balisters_: Upon flat Building they still retained their Name, with this only difference, that such as were placed between the _Angular_ Points, were stiled the _Median_, or middle _Acroteria_. _Annulets_, are little square Parts turned round in the _Corinthian Capital_, under the _Quarter-Round_, called _Echinus_. _Ante_, is a square Pillaster, which the Ancients placed at the corners of the Walls of the Temples. _Amphiprostyle_ from [Greek: amphi], _Circa_, and [Greek: stylos]; _Columna_ was a sort of a Temple which had four Columns in the Front of the Temple, and four in the Face behind.